The present invention relates to a continuous form paper feeder for a printer serving as a terminal output device.
In a conventional printer of this type, fan-fold paper (folded continuous form paper) is used. There are two types of continuous form paper feeders, namely, the push and the pull type.
In a push type continuous form paper feeder, paper is fed upward between a printing head and a platen, and printing can be performed from the upper end of paper. Therefore, so-called "inch cut" can be performed. When printing is frequently performed in a small amount each time, the push type continuous form paper feeder is advantageous.
In a pull type continuous form paper feeder, paper passing through a gap between a printing head and a platen is pulled upward, and the "inch cut" cannot be performed. However, "bottom feed" can be performed wherein paper is inserted from a paper insertion port open widely at the bottom of the printer. In this continuous form paper feeder, paper tension and stiffness need not be taken, into consideration, and paper is rarely ramped or otherwise impeded during feeding. High precision of paper feeding can thus be achieved. Therefore, the pull type continuous form paper feeder is advantageous when printing is performed in a large amount each time.
In the early stage, pull type continuous form paper feeders had been very popular as printers at terminal output devices. However, improved paper holding techniques have been developed, and high-precision push type continuous form paper feeders have also been introduced. In recent years, the push and pull type continuous form paper feeders have become competitive.
Although the conventional push and pull type continuous form paper feeders for printers present unique independent advantages, they have controversial factors. Therefore, it is convenient to use the push or pull type continuous form paper feeder on proper occasions according to conventional applications.
However, conventional printers can employ only a push or pull type continuous form paper feeder. In addition, a tractor unit as a continuous form paper feeder is typically built into or fixed to a printer body. Alternatively, as shown in FIG. 4, even if the tractor unit is detachable from the printer body, the tractor is detached for operational convenience only for feeding or inspection. The tractor unit must be mounted on the printer body at a given position, e.g., the pull feed position in FIG. 4.